• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Self-leveling system for controlling the boom 13 and the bucket 15 by dual action cylinders 17, 19. The system includes a self-leveling valve assembly 27 that includes a first valve portion 27a that includes a flow divider spool 41 so that the flow from the rod end of the boom cylinder 27 is split, a portion of which is a bucket. It flows to the head end of the cylinder 19. The valve assembly also includes a second valve portion 27b comprising a flow split spool 61, whereby the flow from the head end of the boom cylinder 17 is split, a portion of which as the boom 13 is lowered. Flow to the rod end of the bucket cylinder. The self-leveling valve assembly 27 includes the ability to operate the boom cylinder 17 even when the bucket cylinder 19 is fully extended or fully retracted.
    公开号:KR19980070833A
    申请号:KR1019980002238
    申请日:1998-01-24
    公开日:1998-10-26
    发明作者:토드앨덴카세이；아란데비스젝손
    申请人:레슬리 제이 카스퍼；이턴코오포레이숀；
    IPC主号:
    专利说明:

    Double self level valve
    The present invention relates to control for hydraulic systems, and in particular to control valves which achieve automatic leveling of the bucket on the front end of the loader or similar vehicle during the movement of the boom arm to which the bucket is attached.
    Typically, on a vehicle of the type to which the present invention relates, a hydraulic cylinder for controlling the raising and lowering of the boom arm and a separate hydraulic cylinder for adjusting the bucket on the front end of the boom arm are provided. The boom cylinder is controlled by one directional control valve, while the bucket cylinder is controlled by a separate directional control valve. In a hydraulic system of the type to which the present invention relates, the boom cylinder and the bucket cylinder are arranged in a series circuit where fluid flows into the boom cylinder, and then some of the fluid exiting the boom cylinder flows downstream to the bucket cylinder. However, the directional control valve does not necessarily have to be arranged in a series circuit.
    In addition to the boom and bucket cylinders and two directional control valves, the hydraulic pressure system of the present invention includes a self-leveling valve. As will be appreciated by those skilled in the art, in the absence of self-leveling function, it is necessary for the vehicle driver to operate two valves, one on each side, in an effort to maintain the bucket in the level position during boom movement. Those skilled in the art understand that, as used herein, the term level literally means level in the sense of parallel with the ground or simply means that the bucket remains in a constant position during boom movement.
    Commercially used forms of series self-leveling valves are known from US Pat. No. 4,709,618, assigned to the assignee of the present invention and incorporated herein by reference. The self-leveling valve of the cited patent has actually been commercially successful and functions satisfactorily when maintaining the bucket level as the boom rises. However, the self-leveling valve of the cited patent does not include the ability to maintain the bucket level while the boom is lowered.
    US Pat. No. 4,923,362, incorporated herein by reference, illustrates a boom and bucket system for a loader and suggests that the preferred arrangement of the bucket is maintained as the boom is raised or lowered, but the disclosed system is a boom and bucket. In all requires a position feedback sensor. Fluid used to perform bucket leveling is taken from both the boom cylinder return flow and the system pump. In the system of the cited patent, the need for a position feedback sensor is actually put into the overall cost and complexity of the system, and also increases the possibility of failure in the system.
    It is therefore an object of the present invention to provide an improved self-leveling hydraulic system of the type that can hold the bucket in a level position while the boom is raised or lowered.
    A related object of the present invention is to provide an improved self-leveling hydraulic system that does not require in-position feedback sensors and control logic in the form of an open loop to keep the bucket in a level position.
    It is an additional object of the present invention to provide an improved self-leveling hydraulic system which fulfills the above-mentioned objects, in which it is possible to raise or lower the boom even when the bucket has already been fully extended or retracted.
    The above and other objects of the present invention are accomplished by having an improved self-leveling hydraulic system comprising a boom and a bucket and controlling at least two functions. The system includes a double acting cylinder for the boom and the bucket, the cylinder controlling the directional control valve by a separate boom and the bucket, the system having a circuit having a boom cylinder disposed upstream of the bucket cylinder and controlling It further comprises a pressure source for supplying the valve. The first self-leveling valve portion includes a flow splitting valve in fluid communication with the rod end of the boom cylinder, whereby the flow from the rod end of the boom cylinder is divided into first and second flows. The first passage means communicates the first flow to the head end of the bucket cylinder so that as the boom is raised sufficient flow is supplied to maintain the bucket in the level position, and the second passage means communicates the second flow back to the control valve. Let's do it.
    The improved self-leveling hydraulic system is characterized by a second self-leveling valve portion in fluid communication with the head end of the boom cylinder, including a flow splitting valve, whereby flow from the head end of the boom cylinder is directed to the first and second flows. Divided. As the third passage means communicates the first flow to the rod end of the bucket cylinder, sufficient flow is supplied to keep the bucket in the level position as the boom lowers. The fourth passing means communicates the second flow back to the control valve.
    1 is a schematic representation of a self-leveling hydraulic system made in accordance with the present invention.
    FIG. 2 is a longitudinal sectional view showing the top of a self leveling valve schematically shown in FIG. 1; FIG.
    3 is a longitudinal sectional view showing the bottom of the self leveling valve schematically shown in FIG.
    Referring to the drawings, which do not limit the invention, FIG. 1 illustrates an overall hydraulic system comprising a vehicle frame 11 with a boom arm pivotally mounted. A bucket 15 is attached at the forward end of the boom arm 13, the movement of the boom 13 is controlled by the boom cylinder 17, and the movement of the bucket 15 is bucket cylinder 19. Controlled by
    The entire vehicle hydraulic system receives pressurized fluid from the pump 21, the output of which is a directional control valve 23 for controlling the boom cylinder 17, and a directional control valve 25 for controlling the bucket cylinder 19. Is in communication with. Although directional control valves 23 and 25 are essential elements of the overall system, the particular form they take is not an essential feature of the present invention, and any of a number of well known directional control valve forms are used.
    Located between the control valves 23 and 25 and the boom and bucket cylinders 17 and 19, respectively, is the first (or upper) self-leveling valve portion 27a (see FIG. 2) and the second (or lower) self-leveling valve. It is its own valve assembly, denoted 27, which includes a common valve housing 29 having a portion 27b (see FIG. 3) disposed therein.
    In FIG. 1, in conjunction with FIGS. 2 and 3, the valve housing 29 forms a plurality of ports, none of which are actually illustrated as typical ports in FIGS. 2 and 3. However, each port is represented in a drawing drawn in key letters to distinguish it from the rest of the various structural elements. Each port is schematically shown in FIGS. 1, 2 and 3, in which a portion of the valve assembly usually associated with the actual port has an indication of the port. The valve housing 29 includes a port A connected to the head end of the boom cylinder 17; A port B connected to the boom rising side of the control valve 23; A port C connected to the rod end of the boom cylinder 17; A port D connected to the lower side of the control valve 23; A port E connected to the head end of the bucket cylinder 19 and to one port of the bucket control valve 23; A port F is connected to the rod end of the bucket cylinder 19 and the remaining ports of the bucket control valve 23.
    In order to understand the relationship between the upper portion 27a shown in FIG. 2 and the lower portion 27b shown in FIG. 3, the upper portion is well disposed on the upper portion of the lower portion, and is illustrated as ports A, B, E and F. FIG. The core parts of the valve housing 29, designated in 2 and 3, are in open communication directly with each other and immediately above and below each other.
    In the upper portion 27a (see FIG. 2) of the self-leveling valve assembly 27, the valve housing 29 forms a plurality of transverse bores, each of which comprises one or more valve elements (some of which are shown in FIG. 1). Is also identified in the schematic diagram). A load check valve 33 is arranged in the bore 31, and an adjustable hole member 37 is arranged in the bore 35. In the bore 39 a flow divider valve spool 41 is arranged. Finally, a load check valve 45 and an unloading spool 47 are arranged in the bore 43.
    In the lower portion 27b (FIG. 3) of the valve assembly 27, the valve housing 29 forms a large core region 49 as well as a plurality of transverse bores, each of which has one or more valve elements (some of which are shown in FIG. 3). Is also identified in the schematic diagram of 1). In the bore 51 which is in open communication with the core region 49, a load check valve 53 is arranged. In the bore 55 an adjustable hole member 57 is arranged. In the bore 59 a flow divider valve spool 61 is arranged. In the bore 63, a load check valve 65 and an unloading spool 67 are arranged. Finally, a relief valve assembly 70 is disposed in the bore 69.
    Self-leveling boom lift
    In operation, when the vehicle driver wishes to raise the boom 13, while the bucket 15 is at a level (i.e., in a fixed arrangement direction with respect to the ground), the driver turns the directional control valve 23 to that of FIG. Although moving to the right, it is not necessary to move the directional control valve 25 from its neutral (or center) position shown in FIG. As the valve operates, fluid flows from the pump 21 through the valve 23 to the port B. Pressurized fluid entering port B flows through bore 51 at lower portion 27b, then through load check valve 53, exits port A, and then to the head end of boom cylinder 17. Flow.
    As the boom cylinder 17 extends, all of the flow from the rod end of the boom cylinder 17 is communicated back to the port C of the upper portion 27a. Backflow into port C flows through passage 71, in which fluid flows past the adjustable aperture member 37 (not shown in FIG. 1), and then through flow passage 73 through the flow divider. It flows to the left end of the valve spool 41 (in FIG. 2). At the same time, the remainder of the fluid in the passage 71 flows toward the middle of the divider spool 41, and then flows through the fixed aperture 75, and then the fluid radially in the divider spool 41 through the opening 76. It flows outward and then into passage 77, from which it communicates outward through port D and back through the control valve 23 to the system reservoir R. The fluid portion in the passage 71 flowing past the hole member 37 and through the passage 73 is effective to bias the divider spool 41 to the right in FIG. 2. As it occurs, a series of openings 79 formed by the spool 41 cooperate with the core and the passage 81 to form a variable hole (identified 83 in FIG. 1). The fluid flowing through the passage 81 then flows past the load check valve 45, to the port E, and from there to the head end of the bucket cylinder 19.
    As will be appreciated by those skilled in the art, the amount of fluid flowing to the head end of the bucket cylinder 19 relative to the amount of fluid flowing out of the rod end of the boom cylinder 17 to maintain the bucket 15 in the level position. The aperture member 37 that is adjustable to the required amount of fluid should be adjusted appropriately to form a suitable flow slit (ie, of the fluid flowing through the passage 71).
    In addition to unseating the load check valve 45, the pressure in the passage 81 causes the fluid returning from the rod end of the bucket cylinder 19 to the port F to a series of notches on the spool 47. Bias the unloading spool 47 to the right side of FIG. 2 to a position that can flow through 85, then flow to the bottom of passage 77, and combine with flow exiting through port D to reservoir R To return.
    Fully extended bucket cylinder lift
    One of the problems associated with the prior art is that additional boom movement is prevented once the bucket is fully extended or fully retracted in its leveling mode. In view of the serial arrangement between the boom cylinder 17 and the bucket cylinder 19, the boom cylinder 17 is stopped when the boom cylinder 19 once reaches its running limit in any direction in the prior art, because This is because there is a downward obstruction of the flow (i.e., a fully extended bucket cylinder 19).
    According to the invention, once the bucket cylinder 19 is fully extended, there is no longer a need for a flow path to return from the rod end, through the port F and through the unloading spool 47, as previously described. Instead, the fluid between the head end of the bucket cylinder 19 and the load check valve 45 is trapped with the bucket cylinder 19 fully extended. In this state, the fluid in the passage 81 operates on the left end of the unloading spool 47 and moves it to the right side of FIG. 2 (left side in FIG. 1) to a position where one or more openings 87 open to the passage 77. More bias, thereby reducing the pressure in the passage 81 (going through the passage 77 to the port D and the reservoir R) so that the boom cylinder 17 extends the bucket cylinder 19 sufficiently. The boom 13 is continuously raised.
    Lower self-leveling boom
    When it is desirable to lower the boom 13, while maintaining the bucket 15 level, the vehicle driver moves the directional control valve 23 to the left side of FIG. 1 so that the pressurized fluid is released from the pump 21 to the valve 23. Is communicated to port (D). The pressurized fluid there flows past the load check valve 33 and from the port C to the rod end of the boom cylinder 17. As the boom cylinder 17 contracts, the flow from the head end communicates to port A and then flows through passageway 89 at the bottom (FIG. 3). The fluid in the passage 89 flows through the bore 55 and passes through an adjustable and adjustable aperture member 57, the setting of which determines the flow distribution through the flow divider spool 61. A portion of the fluid flow passes through the aperture member 57 and then passes through the passage 91 to the right end of the divider spool 61, biasing the spool 61 to the left side of FIG. 3. As the divider spool 61 is moved to the left, a series of openings 93 in the spool 61 cooperate with the core and the passageway 95 to form a variable hole (identified as 97 in FIG. 1). Fluid flowing through the passage 95 unseats the load check valve 65 and flows from the port F to the rod end of the bucket cylinder 19, as described in connection with the ascending mode of operation. Retract the bucket cylinder at a speed that maintains the level. The remaining fluid in the passage 89 flows through the fixed hole 98 and then exits through the opening 99 in the divider spool 61 and through the core region 49. The low pressure exhaust fluid then flows through port B in core region 49 and returns to reservoir R via control valve 23.
    Lowering the boom with a fully retracted bucket cylinder
    When the boom cylinder 19 is fully retracted, the same problem is indicated as the need to move the boom cylinder as described previously, even when the bucket cylinder 19 cannot move because it reaches its running end. Once the bucket cylinder 19 is fully retracted, the fluid between the port F and the rod end of the bucket cylinder is trapped, and the fluid pressurized in the passage 95 cannot unseat the load check valve 65. It accommodates the above situation in which a relief valve is included. As the pressure in the passage 95 rises, the relief valve 70 is unseated and the fluid pressure in the passage 95 is transferred to the passage 101 in open fluid communication with the core region 49 by the passage 103. Is reduced. Therefore, the fluid reduced by the relief valve 70 communicates to the core region 49 and from there through the port B and back through the control valve 23 to the system reservoir R.
    Those skilled in the art understand that when lowering the boom 13 it is important to be able to keep the bucket 15 in the level position, with or without a load. It is desirable to have the boom cylinder rod to head ratio as 1: 1 as possible, in which case the setting of the pressure relief valve 70 could be near system pressure. However, such is not common, and by way of example assumes a rod to head speed of about .75 million, and if the system pressure is about 2000 psi, then it is desirable to set the relief valve 70 to open below about 1500 psi, Ignore the weight. By using this relationship, the ability to continue to move the boom even when the bucket cylinder is fully retracted is determined. However, the setting of the relief valve 70 must be set to a pressure above that required to curl the bucket 19 (ie, retract the bucket cylinder below the load).
    As is well known to those skilled in the art, if only one wants to operate the bucket cylinder 19, it is necessary to use the directional control valve 25 (FIG. 1) to curl the bucket 15 or to dump the bucket. Simply by moving to the right or left side respectively, thus controlling fluid flow from the pump 21 to the rod end or head end of the bucket cylinder 19 via the valve 25. The mode of operation is well known and does not form part of the invention and is not further described.
    Persons skilled in the art understand that the embodiment of the present invention includes adjustable aperture members 37 and 57, so that the single valve assembly 27 is used on different vehicles, boom and bucket cylinders of different sizes, and various Rod end to head end speed. If a large number of valve assemblies are used in a particular vehicle, the variable bore members 37 and 57 are replaced by some fixed bore member and are selected to suit a particular application, without change in the boom and bucket cylinder.
    As another alternative to the embodiment embodiment, the load check valves 33 and 53 could be replaced by a solenoid valve that could by way of example be normally biased to a closed position such as check valves 33 and 53. If the vehicle driver does not wish to operate the self level characteristic during the ascending mode, he operates the solenoid in place of the load check valve 33. Then, in place of the fluid returning from the rod end of the distributed boom cylinder 17, in order to perform self-leveling, the valve is opened and the fluid returning through port C to the port D and the bucket cylinder ( It only flows back into the system reservoir without the fluid flowing in 19).
    Similarly, if the driver does not wish to operate the self level characteristic while lowering the boom, he operates the solenoid valve in place of the load check valve 53. Then, when the fluid returns from the head end of the boom cylinder 17, it flows to port A, the valve is open, rather dispersed and all of the fluid flows through the bore 51, into the core region 49 and Flow from port B to reservoir R.
    The present invention is described in more detail in the foregoing specification, and various changes and modifications of the present invention will become apparent to those skilled in the art from the reading and understanding of the specification. All such modifications and variations are intended to be included herein as long as they come within the scope of the appended claims.
    The improved self-leveling hydraulic system of the present invention has the effect of keeping the bucket in the level position while the boom is raised or lowered.
    权利要求:
    Claims (5)
    [1" claim-type="Currently amended] A boom 13 and a bucket 15; Separated booms and buckets control the directional control valves 23 and 25, the circuit having the boom cylinders 17 disposed upstream of the bucket cylinders 19, and the pressure source 21 supplied to the control valves. Dual operation cylinders 17 and 19; A first self-leveling valve portion 27a comprising a flow split valve 41 in fluid communication with the rod end of the boom cylinder 17 such that the flow from the rod end of the boom cylinder is divided into first and second flows; ; First passage means for communicating a first flow to the head end of the bucket cylinder 19 to supply sufficient flow to maintain the bucket 15 in a level position as the boom 13 is raised, and a second In a self-leveling hydraulic system having a second passage means (77) for communicating flow back to the control valves (23, 25),
    (a) a second self leveling comprising a flow split valve 61 in fluid communication with the head end of the boom cylinder 17 such that the flow from the head end of the boom cylinder 17 is divided into first and second flows; A valve portion 27b;
    (b) third passing means for communicating a first flow to the rod end of the bucket cylinder 19 to supply sufficient flow to maintain the bucket 15 in a level position as the boom 13 is lowered ( 95);
    (c) a fourth passage means (49) for communicating a second flow back to said control valve.
    [2" claim-type="Currently amended] 2. The bucket according to claim 1, wherein the first leveling valve portion (27a) has both an unloading and a relief function, is arranged in the fifth passing means 43, and the bucket as the boom 13 is raised. Self-leveling hydraulic system, characterized in that it comprises a pilot operated valve means (47) that is normally biased towards a closed position that blocks flow from the rod end of the cylinder (19) to the second passage means.
    [3" claim-type="Currently amended] 2. The second leveling valve portion 27b has a lowering function, is arranged in the sixth passing means 63, 103, and from the head end of the bucket cylinder 19 as the boom is lowered. Self-leveling hydraulic system, characterized in that it comprises a pilot operated valve means (67) which is normally biased towards a closed position blocking the flow to the control valve (23, 25).
    [4" claim-type="Currently amended] 4. The second leveling valve portion (27a) is in fluid communication with the sixth through means (63, 103) from the third through means (95) when the bucket (15) is fully retracted. Self-leveling hydraulic system comprising a relief valve means operable to provide.
    [5" claim-type="Currently amended] 2. The first leveling valve portion 27a is in surface-to-surface engagement with the second self-leveling valve portion 27b and partially open with the second self-leveling valve portion 27b. Self-leveling hydraulic system, characterized in that arranged to communicate.
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    同族专利:
    公开号 | 公开日
    JPH10219730A|1998-08-18|
    EP0856612A1|1998-08-05|
    US5797310A|1998-08-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-01-29|Priority to US08/792,726
    1997-01-29|Priority to US8/792,726
    1998-01-24|Application filed by 레슬리 제이 카스퍼, 이턴코오포레이숀
    1998-10-26|Publication of KR19980070833A
    优先权:
    申请号 | 申请日 | 专利标题
    US08/792,726|US5797310A|1997-01-29|1997-01-29|Dual self level valve|
    US8/792,726|1997-01-29|
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